Metal-polymer laminates for aircraft applications are known in the prior art. For example, Schijve et al U.S. Pat. Nos. 4,489,123 and 4,500,589 disclose laminates reinforced with aromatic polyamide fibers, and Vogelesang et al U.S. Pat. No. 5,039,571 discloses a laminate reinforced with S2-glass fibers. These laminates are being accepted for some aircraft applications because they generally have better mechanical properties and lower specific gravity than aluminum alloys. In addition, they are available at lower cost than fiber-reinforced polymer matrix composites.
Metal-polymer laminates for aircraft applications are presently limited to a maximum width of approximately 152 centimeters (60 inches). This maximum width results from the fact that metal sheet material in the specific alloys, tempers and thicknesses needed for aircraft laminates is restricted by present manufacturing technology to a maximum width of only about 152-165 centimeters (60-65 inches).
The weight of an aircraft fuselage increases in direct relationship with the number of joints between adjacent body panels in the fuselage. The number of joints is inversely related to the width of the body panels. Accordingly, increasing the width of aircraft body panels by splicing or otherwise will directly reduce the fuselage weight.
Although the desirability of splicing adjacent laminated panels to increase their width is readily apparent, until the present invention, there has not yet been developed a satisfactory technique for increasing the width of such panels without detrimentally affecting their mechanical properties.
A principal objective of the invention is to provide a laminated metal-polymer body panel for aircraft applications made with spliced metal layers and having satisfactory mechanical properties. Surprisingly, spliced laminates of the invention have increased residual strength compared with unspliced laminates.
It is a related objective of the present invention to provide an aircraft structure such as a fuselage or wing or empennage, made with laminated metal-polymer body panels and having reduced weight.
Another objective of the invention is to provide an aircraft structure made with laminated metal-polymer body panels and having satisfactory mechanical properties.
Additional objectives and advantages of the present invention will become apparent to persons skilled in the art from the following detailed description.